10-08-2014, 08:15 PM
Cleaning may well do the job. It might be possible to fabricate a new piece if you want to go further. If cleaning restores proper function you may want to just let it be. One of the set screws looks like the head is broken off and considerable rust is present on the others. Set screws can be a real pain to deal with. Use caution with any chemicals to make sure not to get any on plastic materials nearby.
Joe
Joe